The emphasis on intrusion protection devices for residences, office buildings, etc. is widespread today with various alarm systems being proposed as well as such systems being readily available commercially. These intrusion protection devices may include sensors responsive to heat, sound, forced entry and the like which trigger various alarms connected thereto. It has been contemplated that a sensor which is responsive to vibration offers one convenient approach to intrusion protection since it is not uncommon for a intruder to forcibly break into a structure thereby moving a closure such as a window, door or the like. To provide such a sensor responsive to vibration created by forcible entry has met with certain design problems since the sensor must respond to forces of relatively small magnitude which are a common characteristic of an illegal entry. The necessary degree of sensitivity of such a sensor has been difficult to obtain and then only with quite complex electronic circuitry. Such complex electronic devices particularly when designed for use in residences or the like are necessarily high in cost contributing substantially to consumer resistance. Furthermore, present day sensors are usually tailored for a particular installation and therefore do not permit ready interchangability from one location to another in a protected structure.